Vehicle headlight and alert system

ABSTRACT

A vehicle headlight and control system for a bus or large vehicle includes a headlight fixture with a center or low beam light source and side illumination light source operated independently. The side illumination light source may be activated when the vehicle is turning, as detected by the vehicle speed and steering shaft turn angle, to provide supplemental illumination. Both right and left side illumination sources may be provided, and may comprise LED light elements. The system may also include an audible sound generator to alert pedestrians when the vehicle is turning.

RELATED APPLICATION INFORMATION

This application is a continuation of U.S. application Ser. No.13/366,250, filed Feb. 3, 2012, hereby incorporated by reference in itsentirety as if set forth fully herein.

BACKGROUND OF THE INVENTION

1) Field of the Invention

The field of the present invention generally relates to lighting systemsand, more particularly, to a vehicle headlight and control system as maybe used in connection with, among other things, large vehicles andconveyances such as buses, trucks, streetcars, and the like.

2) Background

Proper road illumination is an important factor in allowing drivers toidentify potential road hazards. Transit vehicles, trucks and otherlarge vehicles or conveyances generally employ headlights for providingillumination at nighttime, dusk or in other situations of reducedvisibility. Such headlights are typically forward-facing and thusilluminate primarily in a forward direction, but with some spread oflight fanning out slightly towards either side. Vehicle headlightscommonly include low beams used for general purposes, and high beamsthat may be manually activated in situations requiring additionalillumination.

Because glare from headlights may adversely affect oncoming traffic,transportation regulatory authorities dictate the extent to whichheadlight illumination can spread outward, both in terms of angularspread and intensity. Headlight manufacturers generally must comply withsuch regulations and design headlight illumination patterns accordingly.

For large vehicles, such as buses and trucks, drivers are more prone toexperiencing blind spots while driving or maneuvering. This may occur,for example, where a bus driver attempts to make a right turn. Thedriver may have a difficult time spotting pedestrians crossing a street,or about to cross a street, particularly at nighttime, dusk or other lowlight situations. Likewise, a pedestrian may be unaware that a bus orother large vehicle is about to make a turn across the path where thepedestrian is walking. This lack of visibility presents a potentiallydangerous situation in which serious injuries can occur. Since busesspend considerable time navigating in crowded urban settings, they areat higher risk for encountering these potential situations. While theseproblems are more significant for buses and other large vehicles, theyare also experienced albeit to a lesser degree with smaller vehicles aswell.

Some attempts have been proposed for improving side visibility when avehicle is in the process of turning. For example, under one approach, aheadlight reflector is mechanically tilted sideways as a vehicle turns,based on a detected steering wheel angle. While this approach mayimprove visibility during turning, it requires a mechanical means totilt the headlight reflector, and mechanical parts can be prone to wearand tear or mechanical failure, typically require an electronic controlmeans, and can increase the cost of a headlight unit. Also, merelyadding side illumination may be insufficient to warn pedestrians that avehicle is about to, or in the process of, making a turn.

Other related approaches include the provision of additional lightingsources to supplement the amount of light provided at a side angle asthe vehicle turns. However, those additional lighting sources mayinvolve additional lighting fixtures or units, thus increasing cost andcomplexity.

In addition, many headlights are based on halogen or high-intensitydischarge (HID) light sources. These light sources may have certaindrawbacks, such as excessive energy consumption or frequent replacementrequirements.

Although prior attempts have attempted to solve the aforementionedproblems, they are either costly, complex, incomplete, or inadequateparticularly for larger vehicles. It would therefore be advantageous toprovide a vehicle headlight and control system that solves one or moreof the aforementioned problems, and/or is less complex or costly, morereliable, more energy efficient, longer lasting, and well suited for usein larger vehicles.

SUMMARY OF THE INVENTION

In one aspect, embodiments of the invention as disclosed herein aregenerally directed to a novel and versatile lighting system that isparticularly well suited for a bus, transit vehicle or similarconveyance, but which may find other uses or applications as well.

According to one embodiment as disclosed herein, a vehicle headlight andrelated control system for a transit vehicle includes a fixture with aplurality of light sources, which may be LED-based light sources. Thefixture may include one or more center low beam light sources, and oneor more conditional light sources that are activated when the vehicle isturning or at other appropriate times. In a preferred embodiment, theheadlight fixture includes right and left light sources that areoriented at a side angle, and individually activated as appropriate asthe vehicle turns right or left.

In a preferred embodiment, a control system selectively activates theright and left light sources when the vehicle is in the process of aturning. A detection unit in proximity to the steering column of thevehicle detects a turning angle and relays that information to acontroller. The controller activates the right-facing light source(s) inone or both headlights when the steering wheel has reached a firstturning angle (relative to a zero angle) towards the right direction,and activates the left-facing light source(s) in one or both headlightswhen the steering wheel has reached a second turning angle (relative toa zero angle) towards the left direction. The first turning angle andsecond turning angle may be selected to be the same. The controller alsodeactivates the right-facing or left-facing light source(s), as the casemay be, once the steering wheel has returned towards a central orforward-facing position. In addition to the steering wheel turningangle, the controller may also take account of the vehicle's speed orchange in speed in determining whether to activate or deactivate theright-facing or left-facing light sources.

The control system is also preferably used to control the lowbeamoperation of the headlights, and may further be utilized to control ahighbeam lighting source, whether integrated with the same headlightfixture or provided as a separate fixture.

In other embodiments, a vehicle headlight control system may further beconfigured to include a pedestrian alert system. In one embodiment, thepedestrian alert system includes an audible warning system with anexternal sound source on either side of the vehicle. The external soundsource may be activated when the vehicle is in the process of turning atan intersection or corner, for example at or around the same time thatthe additional light sources for extra turning illumination areactivated. The external sound source may be controlled by the samecontrol mechanism as the vehicle headlights.

Further embodiments, variations and enhancements are also disclosedherein.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram illustrating a perspective view of an example of avehicle headlight fixture in accordance with one embodiment as disclosedherein.

FIG. 2 is a diagram illustrating a front view of the vehicle headlightfixture of FIG. 1.

FIG. 3A is a diagram illustrating a front view of a vehicle headlightfixture similar to the embodiment of FIG. 1, without the cover lens inplace, with another variation in arrangement of the lighting sources.

FIGS. 3B and 3C are perspective views of the vehicle headlight fixtureof FIG. 3A as assembled together with a cover portion, with FIG. 3Cshowing an assembly diagram of separate components of the vehicleheadlight fixture.

FIGS. 3D, 3E and 3F are a rear view, side view, and front viewrespectively of the vehicle headlight fixture illustrated in FIG. 3B.

FIG. 4 is a block diagram of a vehicle headlight control and warningsystem in accordance with one embodiment as disclosed herein.

FIG. 5 is a diagram illustrating an example of a steering wheel turnangle sensor system in accordance with one embodiment as disclosedherein.

FIG. 6 is a diagram illustrating examples of waveforms as may bedetected by the steering wheel turn angle sensor system of FIG. 5.

FIG. 7A is an illustration of a preferred embodiment of a steering wheelturn angle sensor system, including an exploded view of a portionthereof.

FIGS. 7B and 7C are bottom perspective and bottom views, respectively,of the steering wheel turn angle sensor system of FIG. 7A.

FIGS. 7D and 7E are top perspective and top views, respectively, of thesteering wheel turn angle sensor system of FIG. 7A.

FIG. 8 is a diagram illustrating operation of a pair of vehicleheadlights disposed on a vehicle in accordance with one example asdisclosed herein, when the headlights are operating in normal lowbeammode.

FIG. 9 is a photometry diagram showing an example of a light beampattern of an embodiment of a vehicle headlight operating in normallowbeam mode.

FIG. 10 is a diagram illustrating operation of a pair of vehicleheadlights disposed on a vehicle in accordance with one example asdisclosed herein, when the headlights are operating in a left turn mode.

FIG. 11 is a photometry diagram showing an example of a light beampattern of an embodiment of a vehicle headlight operating in a left turnmode.

FIG. 12 is a diagram illustrating operation of a pair of vehicleheadlights disposed on a vehicle in accordance with one example asdisclosed herein, when the headlights are operating in a right turnmode.

FIG. 13 is a photometry diagram showing an example of a light beampattern of an embodiment of a vehicle headlight operating in a rightturn mode.

FIG. 14 is a block diagram of a vehicle headlight and alert system inaccordance with another embodiment as disclosed herein.

FIG. 15 is a diagram illustrating another embodiment of a vehicleheadlight fixture, in front view.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENT(S)

According to various embodiments as disclosed herein, an adaptiveheadlight and control system for a bus, transit vehicle, or otherconveyance may comprise, for example, a fixture having a plurality oflight sources, each of which preferably comprise one more light-emittingdiodes (LEDs) or similar lighting elements, controlled in a manner so asto provide effective illumination when a vehicle is making a relativelysharp turn such as at an intersection or corner. The fixture may includeone or more center low beam light sources and one or more angled lightsources that are selectively activated when the vehicle is turningrelatively sharply, or at other appropriate times. The headlight fixturemay optionally also include a highbeam light source, or may be used inconjunction with a separate highbeam lighting fixture.

In a preferred embodiment, the headlight fixture includes right and leftLED-based light sources that are oriented at a side angle, andindividually activated as appropriate as the vehicle turns right or leftin a relatively sharp manner. In one or more embodiments, a controlsystem selectively activates the right-facing light source on one orboth headlights when the vehicle is in the process of a turningrelatively sharply in a rightward direction, and the left-facing lightsource on one or both headlights when the vehicle is in the process ofturning relatively sharply in a leftward direction. The system ispreferably outfitted with a detection unit for detecting a vehicleturning angle and relays that information to a controller, which in turnselectively activates and deactivates the right and left light sourcesin one or both headlights as needed. In determining whether the vehicleis making a turn at an intersection or corner, the controller may takeaccount of the vehicle's or steering wheel's turning angle as well asthe vehicle's speed or change in speed, and thereby determining whetherto activate or deactivate the right or left light sources.

The vehicle headlight control system may optionally be configured toinclude a pedestrian alert system having, for example, an audiblewarning system with an external sound source on either side of thevehicle. The external sound source on a given side may be selectivelyactivated when the vehicle is in the process of turning in thatdirection at an intersection or corner, and may be activated at oraround the same time that the additional light sources for extra turningillumination are activated.

Embodiments as disclosed herein may provide an adaptive front-lightingsystem which substantially improves vision in a direction of travel,particularly when turning at an intersection or corner for example. Inone or more preferred embodiments, an adaptive headlight systemcomprises a number of LED-based light sources that are selectivelyactivated to provide low-beam operation and enhanced side illuminationwhen turning, as well as optionally high-beam operation andillumination.

FIG. 1 is a diagram illustrating an example of a vehicle headlightfixture 100 in perspective view, in accordance with one embodiment asdisclosed herein. In FIG. 1, the vehicle headlight fixture 100 is shownas assembled, in a manner that may be suitable for installation in avehicle such as a bus or transit vehicle for example. The headlightfixture 100 in this example includes a base portion 106 on which, asillustrated in diagrams described hereafter, the various lightingelements are mounted. The base portion 106 in this example is generallydisc-shaped, with heat dissipating fins 120 disposed on the rear sidealong with an electrical connector 130. The headlight fixture 100further includes a cover housing 105 that is, in this example, generallycylindrical in shape (although other shapes are possible as well),designed to enclose and seal the lighting components of the headlightfixture 100 in an installable unit. At the front end over the coverhousing 105 is disposed a transparent cover 108 that may be, e.g., glassor transparent plastic, polymer or polycarbonate, or any other suitablematerial used in connection with vehicle headlights. The transparentcover 108 may be attached by screwing on to threaded grooves (not shown)on the interior of the cover housing 105, or else by screws (not shown),or by any other suitable or conventional means.

The cover housing 105 and other exposed regions of the headlight fixture100 are preferably made of durable material, such as aluminum, metalalloy, or combinations thereof with carbon fiber or plastic components,suitable to withstand daily wear when disposed in a vehicle, includingvibration, shock and environmental influences. The entire headlightfixture 100 is preferably designed in size and shape suitable for use asa headlight on a bus or transit vehicle, or any other vehicle for whichit may find application.

As also shown in FIGS. 3A-3C, the base portion 106 of the headlightfixture 100 preferably includes a plurality of connection members 123,in this case located around the periphery of the base portion, while thecover housing 105 likewise has a plurality of connection members 122disposed around the periphery of the rear part of the cover housing 105,that generally align with the connection members 123 of the base portion106. In this manner, the cover housing 105 may be suitably attached tothe base portion 106 using screws or other attachment means.

The headlight fixture 100 may further have connection members 113 forfacilitating the attachment of the fixture to an appropriate location atthe front of the vehicle, in a headlight well or similar location, bymeans of appropriate screws 112 or other similar means. In this example,the connection members 113 are disposed around the periphery of the rearpart of the cover housing 105, alternating with the other connectionmembers 122. Other alternative means for attaching the headlight fixture100 to a vehicle may be used as well.

Additional details are shown in FIG. 2, which is a front view diagram ofthe vehicle headlight fixture 100 of FIG. 1. As shown in FIG. 2, thelighting fixture 100 may include a center forward-facing low beam lightsource 152, and a second low beam light source 171 which, in thisexample, is directed towards a lens 160 which disperses the light in aspreading pattern outwards at a predefined angle, and also directs thespread light downwards. Preferably, the combination of light sources 145and 148 combine to provide a complete low beam lighting pattern that issubstantially in compliance with applicable regulatory requirements forlow beam lighting. Lens 160 may be, for example, a biconcave varietywith attributes selected so as to achieve a beam pattern similar to thatshown in FIG. 9, or any other suitable variety of lens. As analternative to using a lens 160 to spread and redirect the light fromlight source 171, other means may be used to achieve a similar result;for example, the light source may be pointed downwards towards an angledreflector, which disperses the light in a spreading pattern outwards ata slight angle, and generally directed slightly towards the ground.

In a preferred embodiment, the light sources 152 and 171 are LED basedlight sources, and may each comprise “super-bright” LED lightingelements of sufficient luminosity to provide illumination out to therequired distance of visibility for conventional lowbeam operation.Suitable LEDs may be obtained, for example, from Philips LumiledsLighting Company, or other providers, and may be sold under thetradenames such as Luxeon® Altilon. Such LEDs may be 7.0 Watts, 13.7Watts, or any other suitable power rating. The LEDs may be cool white incolor, close to daylight in color temperature, to enhance theirprojection distance and maximize visibility. In alternative embodiments,other numbers and arrangements of LEDs may be used in order to obtainthe desired intensity and beam spread pattern.

As further illustrated in FIG. 2, the lighting fixture may additionallyinclude a pair of side-mounted angled lighting units 150, 151 that areselectively activated to provide illumination during vehicle turns or inother appropriate circumstances. In this example, each lighting unit150, 151 comprises a generally cylindrical housing, as illustrated inFIG. 2, for channeling light generated by the lighting sources 140, 141,and each is oriented at a fixed angle with respect to the back plane ofthe lighting fixture and slightly downward (although they may also belevel), such that the lighting sources 140, 141 in the lighting units150, 151 shed their light at a partial side angle to the left or rightdirection of the vehicle (i.e., at an acute angle relative to the mainprojected beam from center light source 152). The light sources 140, 141are preferably LED light sources, and may each may again comprise“super-bright” LED lighting elements of sufficient luminosity to provideillumination out to the required distance of visibility for the turningoperation. As with the lowbeam LEDs, the LEDs used for light sources140, 141 may be cool white in color, close to daylight, to enhance theirprojection distance and maximize visibility. The light sources 140, 141may come pre-mounted or else may be mounted on a suitable mountingsurface.

FIGS. 3A through 3E provide further details of the vehicle headlightfixture 100, with and without the cover 109 attached. FIG. 3A is adiagram illustrating a front view of the vehicle headlight fixture 100,without the cover lens in place, showing again the various connectionmembers 122 and 113 disposed around the periphery of the rear part ofthe cover housing 105. Similar to FIG. 2, the headlight fixture 100includes a first center light source (shown as 152 in FIG. 2) disposedbehind a forward-facing lens 145 for lowbeam operation, along with asecond forward-facing light source 171 whose output is adjusted in termsof beam direction and/or spread by lens 160, so as to provide someoutward spread of light and also face slightly downwards towards theroadway. As before, the combined lighting pattern of lighting sources145 and 171 preferably combine to provide a complete lowbeam lightingpattern in substantial compliance with applicable regulatoryrequirements. The headlight fixture 100 also includes a pair ofside-mounted angled lighting units 150, 151 that are selectivelyactivated to provide illumination during vehicle turns or in otherappropriate circumstances.

FIG. 3C is an assembly view diagram showing some of the separatecomponents of the vehicle headlight fixture 100 illustrated in FIGS. 3Aand 3B. In FIG. 3C, the cover housing 105 is substantially similar tothat shown in FIGS. 1 and 2, with the connection members 122 and 113around the periphery of the rear portion of the cover housing 105, whichfurther has a lip 166 disposed around the outer edge to enhance sealingof the components within the headlight fixture 100. The base portion 106also resembles that of FIG. 1. As can be seen in FIG. 3C, the baseportion 106 of the cover housing includes a mounting element 170 in theform of an H-bracket or similar structure, with lighting element 171mounted on a cross-beam of mounting element 170 and the lens 160 mountedat the terminating end of the H-bracket mounting element 170. As notedpreviously, the lens 160 may be, for example, a biconcave variety withattributes selected so as to achieve a beam pattern similar to thatshown in FIG. 9, or any other suitable variety of lens. A perpendicularmounting platform 172 may be provided for additional support of themounting element 170, and may include right and left projecting arms forholding the cylindrical housings of the angled side-mounted lightingunits 150, 151. FIG. 3C also illustrates the screws 169 that may be usedas attachment means to connect together the base portion 106 and thecover housing 105. FIG. 3B illustrates the unit as assembled, whichappears substantially the same in outward appearance as the fixture 100illustrated in FIG. 1.

FIGS. 3D, 3E and 3F are a rear view, side view, and front viewrespectively of the vehicle headlight fixture 100 illustrated in FIG.3B, as fully assembled, with the cover lens 108 in place.

FIG. 15 is a diagram illustrating an example of another embodiment ofvehicle headlight fixture 1500, in front view (similar to FIG. 2). Forconvenience, elements similar or analogous in function and form withthose in the embodiment of FIGS. 1 and 2 have been numbered similarly inFIG. 15. The main difference in the embodiment of FIG. 15 is that theupper light source 1548, instead of being directed forwardly, instead ismounted to the bottom surface of a protruding L-shaped bracket 1547, andis facing downwards. The bracket 1547 is secured also to the base 106 ofthe cover shell by, e.g., screws or other fastening means. Light fromthe upper light source 1548, which may be embodied as a light-emittingdiode for example, is directed downwards towards an angled reflectorplate 1549 that disperses the light in a spreading pattern outwards at aslight angle, and generally directed slightly towards the ground. Aswith the prior embodiment, the lower light source 152 directs its lightforwardly towards, e.g., a lens (depicted in FIG. 15 as framed lens1545). Preferably, the combination of light sources 1548 and 152 combineto provide a complete low beam lighting pattern similar to FIG. 9 andthat is substantially in compliance with applicable regulatoryrequirements for low beam sources.

A variety of other light source arrangements and configurations mayalternatively be utilized to generate the low beam or, in some cases,the other beam patterns disclosed herein.

As noted previously, the headlight fixture in accordance with theembodiments disclosed herein is preferably used in connection with a busor other large vehicle (although it may find use in smaller vehicles orother settings as well); in such a case, a pair of right and leftheadlight fixtures may be advantageously operated so as to providesuitable side-illumination to a driver of a vehicle when turning at anintersection or corner, for example. FIG. 4 is a block diagram of avehicle headlight control and warning system 400 in accordance with oneembodiment as disclosed herein, meeting such a purpose. In FIG. 4, aright headlight fixture 405 and a left headlight fixture 406 areoperably coupled to a headlight control module 430, and controlled viacontrol signals 445, 446 respectively. The right and left headlightfixtures 405, 406 may each be embodied in the form of the headlightfixture illustrated in FIG. 1-2 or 3A-3F, or any other suitableembodiment. The right and left headlight fixtures 405, 406 preferablyinclude both lowbeam lights and conditionally activated sideillumination lights, although they may also include highbeam lights orother combinations of lighting elements.

The headlight control module 430 receives an incoming power supplysignal 450 which may be, for example, a 24-Volt input derived from thevehicle's battery. The headlight control module 430 also preferablyreceives a control signal (or set of control signals) 421 from a vehiclecontrol system 410. The vehicle control system receives a steeringposition sensor signal 421 generated by a steering position sensor 420.The vehicle control system 410 may include a number of vehicle controlmodules that, for instance, provide control, sensor, indicator, ordiagnostic information for various systems including the lightingsystem, dashboard indicators, braking system or sensors, engine/speedcontrols or sensors, door controls and sensors, and the like. In otherembodiments, the steering position sensor signal 421 may bypass thevehicle control system 410 and be provided to the headlight controlmodule 430, in the case where the latter includes the control and logicfunctionality described in more detail below.

The headlight control and warning system 400 of FIG. 4 further includesa pedestrian alert function operable through the headlight controlmodule 430. As part of the pedestrian alert function, a right sideaudible sound generator 435 and a left side audible sound generator 436are disposed on the right and left sides of the vehicle, respectively,and may be activated at appropriate times to alert pedestrians that thevehicle is turning at an intersection or corner. The audible soundgenerators 435, 436 may, for example, each constitute a buzzer or chimethat is controlled via the headlight control module 430, and they may beused in conjunction with other alert indicators including flashinglights.

In operation, the control system 410 receives (by polling or otherwise)periodic indications of the turn angle of the vehicle via the steeringposition sensor signal 421 from the steering position sensor 420. Thecontrol system 410 may also optionally receive a speed indication signal(not shown) and, based on the vehicle speed over a period of time,calculate the vehicle's acceleration or deceleration in astraightforward manner. The control system 410 delivers controlsignal(s) 431 to the headlight control module 430 to control operationof the right and left headlight fixtures 405, 406 as well as the audiblesound generators 435, 436 by activating and deactivating them inaccordance with the operation of the vehicle. For example, the controlsystem 410 may instruct the headlight control module 430 to activate thelow beam lights in the right and left headlight fixtures 405, 406 inresponse to a manual switch setting controlled by the vehicle driver.Further, in a preferred embodiment, the control system 410 determines,based at least on the turning angle of the vehicle (as indicated by thesteering position sensor signal 420), whether the vehicle is turning atan intersection or corner, and if so issues control signal(s) 431 to theheadlight control module to activate the side illumination lights of theright and/or left headlight fixtures 405, 406, and optionally the rightor left audible sound generator 435 or 436.

For example, when the steering position sensor signal 421 detects thatthe steering wheel is turned beyond an angle indicating that the vehiclewheels are beyond a certain angular threshold (such as, e.g., 20 degreesto the right or left off the centerline, or some other programmedtrigger angle), then the control system 410 may issue an activationsignal to initially turn on the right-facing light elements in the rightand left headlight fixtures 405, 406 if the vehicle is turning in aright direction, or to initially turn on the left-facing light elementsin the right and left headlight fixtures 405, 406 if the vehicle isturning in a left direction. Preferably, the side illumination lightingelements in both right and left headlight fixtures 405, 406 aresimultaneously activated to provide side illumination in the directionof the vehicle's turning, although in other embodiments only the sideillumination lighting element of the lighting fixture on the side of thevehicle in the direction of the turn is activated. The side illuminationlighting elements are preferably activated for the duration of thevehicle's turn. In order to prevent flicker, the control system 410preferably imposes a suitable level of hysteresis, such that in order todeactivate the side illumination lighting elements the vehicle wheelsneed to cross some angle less than original threshold (for instance, 18degrees if the original trigger angle was 20 degrees) prior todeactivating the side illumination lighting elements.

In alternative embodiments, further criteria may be employed todetermine whether or not to activate the side illumination elements. Forexample, the control system 410 may utilize the vehicle speed, itsacceleration/deceleration, and the steering position sensor signal 421to determining whether the vehicle is turning at an intersection orcorner, and if so issues control signal(s) 431 to the headlight controlmodule to activate the side illumination lights of the right and/or leftheadlight fixtures 405, 406, and optionally the right or left audiblesound generator 435 or 436.

As example of this operation, when the vehicle is in a low speed range(such as, e.g., less than 30 miles per hour or some other programmedspeed threshold) or is in a medium speed range (such as, e.g., less than40 miles per hour or some other programmed speed threshold) and rapidlydecelerating, and when the steering position sensor signal 421 indicatesthat the steering wheel is turned beyond an angle such that the vehiclewheels are beyond a certain angular threshold (such as, e.g., 20 degreesto the right or left off the centerline, or some other programmedangle), then the control system 410 may issue an activation signal toinitially turn on the right-facing light elements in the right and leftheadlight fixtures 405, 406 if the vehicle is turning in a rightdirection, or to initially turn on the left-facing light elements in theright and left headlight fixtures 405, 406 if the vehicle is turning ina left direction. Preferably, the side illumination lighting elements inboth right and left headlight fixtures 405, 406 are simultaneouslyactivated to provide side illumination in the direction of the vehicle'sturning, although in other embodiments only the side illuminationlighting element of the lighting fixture on the side of the vehicle inthe direction of the turn is activated. The side illumination lightingelements are preferably activated for the duration of the vehicle'sturn. In order to prevent flicker, the control system 410 preferablyimposes a suitable level of hysteresis, such that in order to deactivatethe side illumination lighting elements the vehicle wheels need to crosssome angle less than original threshold (e.g., 18 degrees if theoriginal trigger angle was 20 degrees) and/or must exceed the maximumspeed by some additional delta. If either the required turning angle orspeed is no longer met, after application of suitable hysteresis, thenthe control system 410 will issue a deactivation signal (or deassert anexisting activation signal) for the right or left headlight fixture 405,406 as the case may be.

Optionally, at the same time the right or left headlight fixture 405,406 is activated during a vehicle turn, the control system 410 furtherinstructs the headlight control module 430 to activate the audible soundgenerator 435 or 436 in the direction of the vehicle's turn. The audiblesound generator 435 or 436 preferably generates a buzzer noise or chimein order to warn pedestrians that the vehicle is turning. In certainembodiments, the warning may be supplemented or augmented by causing theside illumination light elements of the headlight fixtures 405, 406 toflash or strobe one or more times during the vehicle's turning maneuver.The flashing or strobing operation may be a programmable option selectedby modifying suitable parameters with the control system 410. Theaudible sound generators 435, 436 may be deactivated in tandem with thesupplemental illumination provided by the headlight fixtures 405 and406, or else may be independently deactivated after a predeterminedamount of time has elapsed, or otherwise. The audible sound generators435, 436 may also be configured so as to operate only when the vehicleis in motion, so that if the vehicle has halted the sound temporarilystops as well.

In an alternative embodiment, the vehicle is further outfitted withultrasonic motion sensors (not shown) on either forward flank of thevehicle, near the location of the sidelights or front corner of thevehicle. The appropriate ultrasonic motion sensor is activated when thevehicle is turning relatively sharply, at an intersection or corner. Ifthe ultrasonic motion sensor detects the presence of an individual, itthen activates the appropriate right or left audible sound generator 435or 436 as the case may be, so long as the motion is detected oralternatively for a predetermined amount of time.

In the foregoing manner, the headlight control and warning system 400 ofFIG. 4 may provide both useful side illumination for the vehicle driverwhen turning the vehicle at an intersection or corner, as well asaudible and possibly visual alerting to pedestrians who may be inproximity of the vehicle.

FIGS. 8 through 13 illustrate examples of operation of the headlightsystem as employed, for example, in a bus or other transit vehicle.First, FIG. 8 is a diagram illustrating operation of a pair of vehicleheadlights disposed on a vehicle 820 when the headlights are operatingin normal lowbeam mode. As shown in FIG. 8, the headlight beams 825, 826are each oriented along a straight centerline 835, 836 emanating fromthe respective left and right headlights. In this case, the headlightbeams 825, 826 each fan out in a beamspread of approximately 18 degreesto the right and left of each centerline 835, 836 according to aphotometry diagram similar to the one shown in FIG. 9, to form acombined lowbeam pattern.

FIG. 10 is a diagram illustrating operation of a pair of vehicleheadlights disposed on a vehicle 1020 in accordance with an example whenthe headlights are operating in a left turn mode. As shown in FIG. 10,the headlights continue to produce headlight beams 825, 826 that fan outalong the centerlines 835, 836 in an 18 degree spread. In addition, eachof the headlights also generates a left side illumination pattern usingthe left-facing lighting elements of each headlight fixture, orientedalong angled lines 1045 and 1046 respectively, generating additionalbeams 1025 and 1026 respectively. The angled lines 1045, 1046 are eachoffset at a predefined angle, in this case 35 degrees, such that thetotal beamspread to the left of the vehicle is 53 degrees (as thelightbeam 1025 along angled line 1045 spreads out an additional 18degrees from the angled line 1045). The resulting beam pattern issimilar to the one illustrated in the photometry diagram of FIG. 11 forone of the vehicle headlights operating in a left turn mode.

Similarly, FIG. 12 is a diagram illustrating operation of a pair ofvehicle headlights disposed on a vehicle 1220 in accordance with anexample when the headlights are operating in a right turn mode. As shownin FIG. 12, the headlights continue to produce headlight beams 825, 826that fan out along the centerlines 835, 836 in an 18 degree spread. Inaddition, each of the headlights also generates a right sideillumination pattern using the right-facing lighting elements of eachheadlight fixture, oriented along angled lines 1245 and 1246respectively, generating additional beams 1225 and 1226 respectively.The angled lines 1245, 1246 are each offset at a predefined angle, inthis case 35 degrees, such that the total beamspread to the right of thevehicle is 53 degrees (as the lightbeam 1225 along angled line 1245spreads out an additional 18 degrees from the angled line 1245). Theresulting beam pattern is similar to the one illustrated in thephotometry diagram of FIG. 13 for one of the vehicle headlightsoperating in a right turn mode.

As shown in the foregoing examples, a vehicle can be provided withsupplemental illumination when turning or cornering, thereby increasingsafety and driver visibility. As illustrated in FIGS. 11 and 13, thesupplemental illumination can be directed in a generally downwarddirection, ranging from 5 degrees to nearly 25 degrees off thehorizontal in this example, and gradually tapering downward withbeamspread toward the outer periphery so as to reduce the possibility ofinterference with oncoming traffic. Of course, the beam patterns inthese examples are merely illustrative and should not be taken to bespecifically limiting in any manner.

FIG. 5 is a diagram illustrating an example of a steering wheel turnangle sensor system in accordance with one embodiment as disclosedherein, as may be used in connection with the control system of FIG. 4or other related systems for controlling headlight fixtures on avehicle. As shown in FIG. 5, the steering wheel turn angle sensor systemincludes, in this embodiment, a pair of magnetic collars 531, 532disposed around a steering wheel shaft 510 or member that rotates inconjunction with the steering wheel shaft, in response to a drivermanually turning the vehicle's steering wheel 502. The magnetic collarsare proximate to a detection mechanism 550, such as a unit comprising acircuit board 520 having mounted thereon a pair of integrated circuit(IC) sensors 521, 522, each of which is positioned adjacent to one ofthe magnetic collars 531, 532 for detecting the relative motion thereof.The magnetic collars 531, 532 may each comprise an alternating patternof oppositely magnetized (north and south) individual magnetic elements541 or 542, each preferably being the same size. In this example, themagnetic elements 541, 542 are rectangular (or square) in shape. Thepattern of the first magnetic collar 531 is preferably offset from thepattern of the second magnetic collar 532, such that the magneticelements 541 of the first collar 531 are midway between the magneticelements 542 of the second magnetic collar 532 along the circumferentialperimeter of the steering wheel shaft 510.

The IC sensors 521, 522 may each comprise a Hall effect sensor fordetecting magnetic flux from each of the magnetic collars 531, 532 asthe steering wheel shaft 510, and hence the magnetic collars 531, 532,are rotated in either direction. The IC sensors 521, 522 may, forexample, each constitute a rotary position sensor IC such as a modelMLX90316 monolithic sensor IC as manufactured by Melexis MicroelectricIntegrated Systems of Belgium, or any other suitable IC or other sensor.The IC sensors 521, 522 may provide an output signal in the form of apulse-width modulated signal or in any other suitable format, which isprovided to a controller (such as the control system 410 in FIG. 4) forfurther analysis and processing. The output signal from IC sensor 521may be high when the magnetic element 541 proximate the IC sensor 521 is“north” in magnetization and low when the magnetic element 541 proximatethe IC sensor 521 is “south” in magnetization.

The controller preferably interprets the output signals representing themagnetic transitions between north and south elements of the magneticcollars 531, 532 in order to determine whether the steering shaft isturning in a right or left direction, and how far the steering wheel hasturned in that direction. Each element 541 and 542 of the magneticcollars 531, 532 is of fixed length and corresponds to a predeterminedangular displacement of the steering wheel shaft 510 with respect to areference location, which is the cross-axis traversing the location ofthe IC sensors 521, 522 in this example. With each north/south orsouth/north transition, the controller can determine that the fixedangular distance corresponding to a length of one magnetic element 541or 542 has been traversed, so long as the steering wheel continues tomove in the same direction. The direction of travel of the steeringwheel shaft 510 can be detected by comparing the output signals fromboth IC sensors 521, 522 (whereas a single magnetic collar and IC sensormay be insufficient to provide directional information).

This operation may be explained with reference to the waveform diagramsof FIG. 6, which represent output waveforms 601, 650 from IC sensors 521and 522 respectively. As shown in FIG. 6, the output waveform 601 has aseries of peaks high pulses 611, 613, 615 that correspond to when themagnetic collar 531 is proximate an element 541 with “north”magnetization, whereas the low values between the pulses 611, 613 and615 represent the times when the magnetic collar 531 is proximate to anelement 541 with a “south” magnetization. Similarly, the output waveform650 has a series of peaks high pulses 651, 653, 655 that correspond towhen the magnetic collar 532 is proximate an element 542 with “north”magnetization, whereas the low values between the pulses 651, 653 and655 represent the times when the magnetic collar 532 is proximate to anelement 542 with a “south” magnetization. The positive transitions ineach waveform 601, 650 represent south/north transitions, and thenegative transitions in each waveform 601, 650 represent north/southtransitions. So long as the waveforms alternative such as shown in FIG.6, it means that the steering wheel 502 (i.e., steering wheel shaft 510)is continuing to turn in the same direction. If, however, twoconsecutive transitions occur in the same waveform 601 without anintervening transition in the other waveform 650, or vice versa, thissignifies that the steering wheel shaft 510 has changed direction and isturning in the opposite direction. More generally, an even number oftransitions occurring in the same waveform before a transition in theother waveform occurs indicates a change in direction, while an oddnumber of transitions occurring in the same waveform prior to atransition in the other waveform indicate that the steering wheel shaftis continuing to turn in the same direction. Multiple transitions canoccur in one waveform 610 or 650 without any transition in the otherwaveform during periods where the steering wheel is being keptrelatively steady along a certain path.

To keep track of the motion of the steering wheel, the controllerpreferably maintains the current direction of the steering column(clockwise or counter-clockwise, corresponding to right and leftrespectively) in a working variable or storage element, and furtherstores the number of transitions offset from the zero point that havebeen detected. With this information, the controller can determine theprecise steering wheel angular position at any given instant in time,and hence the turning direction of the vehicle.

In a preferred embodiment, when the steering wheel sensor system isfirst employed in the vehicle, the zero point (dead center) of thesteering wheel shaft 510 when the vehicle is oriented in a straight andforward direction is measured and durably stored in the controller, forexample in a flash memory. At that point in time, the left and rightdirections for the control signals may also be defined and stored inflash. Preferably, each time the vehicle is stopped the steering wheelcolumn position is saved to durable memory. When the vehicle starts upagain, the steering wheel column position is read out from the durablememory and utilized by the controller. In other embodiments, thesteering wheel sensor mechanism may be further outfitted with a thirdmagnetic element that denotes the centerpoint of the steering column, toprovide an additional mechanical means for determining or verifying thecenter of the steering wheel shaft 510.

In yet another embodiment, the controller may be provided with aself-calibration routine for calibrating or verifying the calibration ofthe steering wheel sensor mechanism during operation. In this example,it is assumed that when the vehicle is traveling at a high speed for anextended period and no IC sensor transitions are detected, that it istraveling in essentially a straight line at dead center. For example ifthe vehicle is traveling over 40 miles per hour for 20 or 30 seconds, itmay be assumed to be traveling in a straight line at dead center, andthe controller may update its sensor status information accordingly.

FIGS. 7A through 7E illustrate a preferred mechanical mechanism for asteering wheel turn angle sensor system as may reflect a particularimplementation of the system illustrated in FIG. 5. FIG. 7A shows, forexample, a steering wheel 702 mounted to a steering wheel shaft 710,having a steering column enclosure 760 disposed around the upper portionof the shaft 710 proximate the steering wheel 702. The steering columnenclosure 760 remains stationary as the steering wheel shaft 710 rotatesclockwise or counterclockwise within a central cavity thereof. Asteering wheel turn angle detector 750 (such as illustrated in FIG. 5)is disposed proximate to the steering wheel shaft 710, and is secured byan arrangement included a pair of outer arms 763 connected to a collar775 (see FIG. 7C) surrounding the lower part of the shaft 710 and a pairof upper arms 762 connected to the steering column enclosure 760. Theouter arms 763 are securably attachable to the vehicle frame itself, andremain stationary as the steering wheel column 710 rotates. The steeringwheel turn angle detector 750, as shown in the exploded view within FIG.7A, may include a printed circuit board 720 that is attached to theouter arms 763 with a spring clip 724 or other mechanism. A steeringwheel shaft collar 731 preferably comprising at least two magneticcollars is preferably disposed around the steering wheel shaft 710 androtates therewith. The operation of the magnetic collars with respect toIC sensors located on the PC board 720 is preferably similar to theoperation as described in connection with FIGS. 5 and 6.

FIGS. 7B and 7C are bottom perspective and bottom views, respectively,of the steering wheel turn angle sensor system of FIG. 7A, showingadditional details thereof from other angles, with like componentssharing the same reference numbers as in FIG. 7A. Likewise, FIGS. 7D and7E are top perspective and top views, respectively, of the steeringwheel turn angle sensor system of FIG. 7A also showing additionaldetails. Among other things, these figures show a securing member orbracket 770 which securably attaches a protective collar shell 773 tothe circuit board 720 to improve the mechanical stability of thecomponents.

FIG. 14 is a block diagram of a vehicle headlight and alert system 1400in accordance with another embodiment as disclosed herein, showing theelectrical interconnections thereof. As illustrated in FIG. 14, aheadlight control module 1430 is connected to a communication bus, suchas a Local Interconnect Network bus (LIN-bus) 1431, which is coupled toa vehicle control system 1410. The control system 1410 receives steeringangle sensor position signals 1421 from a steering position sensormodule 1420, and may also receive a vehicle speed sensor signal 1463from a vehicle speed sensor 1462 and ultrasonic sensor input signals1461 from an ultrasonic sensor 1460, if provided. The control system1410 also receives or is otherwise programmed with programmableparameters (not shown in FIG. 14) such as, for example, threshold orother parameters used for detecting when the vehicle is turning orcornering, and parameters selecting whether the supplementalillumination lights will flash during turning and whether the optionalaudible sound generators will be utilized. The control system 1410 alsoreceives manual commands 1481 and 1482 for turning the lowbeam andhighbeam lights on or off.

The control system 1410 is electrically coupled to a power regulator1412 that preferably derives power from an onboard battery supply powertrunk or cable, such as a 12-Volt battery generated power source. Thecontrol system 1410 may be coupled to a power control bus 1455 thatprovides power signals to downstream components (such as the variousheadlight modules), and to a selection control bus 1456 that conveyssignals for selectively engaging the various headlight modules orelements thereof and, if provided, the audio warning speakers 1498,1499.

In terms of outputs, the control system 1410 may be operably coupled toa highbeam headlight control module 1471 which may comprise, forexample, a boost/buck LED regulator as may be implemented using anLM3429 power controller manufactured by National Semiconductor,controllably connected to a highbeam headlight fixture 1491. The controlsystem 1410 is further operably coupled to a lowbeam headlight controlmodule 1472 which may comprise, for example, a buck LED regulator as maybe implemented using an LM3404 power controller manufactured by NationalSemiconductor, controllably connected to lowbeam power inputs of amulti-mode headlight fixture 1492 which may be embodied, for instance,as the headlight fixture illustrated in FIG. 1-2 or 3A-3E. The controlsystem 1410 is further operably coupled to a side illumination headlightcontrol module 1473 which may comprise, for example, another buck LEDregulator as may be implemented using an LM3404 power controller. Theside illumination headlight control module 1473 outputs a power signalto a pair of power switches 1475, 1476, which provide outputsrespectively to the right side illumination power inputs 1495 and theleft side illumination power inputs 1496 of the multi-mode headlightfixture. Power switches 1475, 1476 are operated under control of thecontrol system 1410, and are activated when appropriate to allow theside illumination elements to be turned on. In each case, the controlsystem 1410 provides on/off commands to the highbeam control module1471, lowbeam control module 1472, and side illumination headlightcontrol module 1473, via the selection control bus 1456, as well aspower control (e.g., pulse-width modulation) parameters or controlsignals via the power control bus 1455.

In addition to the illumination controls, the control system 1410 mayalso provide output driver signals to the drivers 1478, 1479 for theright audio sound generator (warning speaker) 1498 and left audio soundgenerator (warning speaker) 1499 respectively.

The control system 1410 thereby may provide comprehensive and flexiblecontrol of the illumination and audible components of the headlight andalert system disclosed herein.

In addition, the controller 410 (FIG. 4) or control system 1410 (FIG.14) may further provide the ability of the headlight to operate asdaylight running lights. For example, when the headlights are off, or inresponse to a manual command, the controller or control system mayprovide a reduced current to the headlights (for instance, at a 50%level) so that they are operating at approximately at a reduced fraction(e.g., half) of their normal output. The daylight running lights mayalso be triggered by a light sensor, and operate in conditionsapproximating normal daytime lighting conditions.

In certain embodiments, multiple light elements (e.g., LEDs) may beoriented in a particular direction. In such a case, the controller mayoptionally be configured, for example, to activate a first right-facinglight element in one or both headlights when the steering wheel hasreached a first turning angle (relative to a zero angle) towards theright direction, and activate a second right-facing light element in oneor both headlights when the steering wheel has reached a second sharperturning angle towards the right direction. Likewise, the controller maybe configured to activate a first left-facing light element in one orboth headlights when the steering wheel has reached a first turningangle (relative to a zero angle) towards the left direction, and toactivate a second left-facing light element in one or both headlightswhen the steering wheel has reached as second sharper turning angletowards the left direction. The same principle may be applied foradditional light elements, with each added light element or set of lightelements triggered by a sharper angle to increase brightness as theturning angle becomes more pronounced.

In one or more aspects of the instant disclosure, a versatile and novelvehicle exterior illumination system and pedestrian alert system isprovided. One or more multi-mode lighting fixtures encased in headlightenclosures may be installed in a vehicle, such as a bus or transitvehicle, to provide adaptive forward and side exterior illumination forthe vehicle. The adaptive illumination provided by the multi-modeheadlight fixtures may be based on LED-type light sources comprisingboth forward facing LED lights and additional angled LED lights that areselectively activated during a vehicle turn. The angled LED-based lightscan, for example, project light in a direction of travel of the vehicleupon detecting a turn to provide advantages including, but not limitedto widened peripheral viewing for a driver, greater visual presence to anearby pedestrian, and ensuring passenger safety upon engaging in a turnor other vehicle movement. The light emitted by the LED-based headlightfixtures may be similar to daylight, which may be gentler on the eyesand therefore increase driver comfort during nighttime operation of thevehicle.

In various embodiments, an LED-based headlight and alert systemconstructed in accordance with the principles and techniques disclosedherein may exhibit a number of advantages and/or useful characteristics.For example, such a system may provide increased safety and visibility,thus reducing accidents and potential injuries. In addition, the LEDheadlight fixtures may have a long lifetime because LEDs require lessfrequent replacement over time as compared with, e.g., incandescent orhalogen lights. This can reduce maintenance costs (both replacementcomponent costs and service costs). LED lights are power efficient andthus can result in significant power savings.

While preferred embodiments of the invention have been described herein,many variations are possible which remain within the concept and scopeof the invention. Such variations would become clear to one of ordinaryskill in the art after inspection of the specification and the drawings.The invention therefore is not to be restricted except within the spiritand scope of any appended claims.

What is claimed is:
 1. A multi-mode headlight fixture, comprising: aheadlight enclosure; a lowbeam light source within the headlightenclosure; a side illumination light source within the headlightenclosure operable independently from the lowbeam light source; and acover lens attached to the headlight enclosure.